Fourdrinier machine



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Patented Apr.` 24, 1951 attain UNITED STATES entspr ortica FOURDRINIER MACHINE Harry H. Hart, Wilmington, Del., assigner to The Pusey & Jones Corporation, Wilmington, Del., p a corporation of Delaware Application June 9, 1947, Serial No. 753,496

The present invention relates to a new method land apparatus for changing thescreens of Fourdrinierpaper making machines. `More. particularly, the invention provides a new, improved vand greatly simplied Fourdrinier machinestructure, adapted to cooperate with a new type of pliable, flexible, tough, non-metallic Fourdrinier screen, and to a new method of installing such a screen on the machine.

in the'past, endless Fourdrinier screens of bronze yor other metal alloy wire have been employed exclusively in the manufacture of paper on Fourdrinier machines. Such screens have numerous inherent disadvantages, but are the best that the art had produced, prior to the development of the strong, tough, pliable, highly flexible synthetic screen, formed. of a woven mesh of single strands of unitary laments of nylon or the like. The prior bronze screens,

although extremely expensive, were short-lived and had to be replaced after approximately thirty days use. Moreover, the replacement operation was slow and` costly, not only because of the labor involved in the screen changing operation but because of the fact vthat the mill had to be shut down, resulting in a complete loss of production. Y

In an eiort to speed up the screen changing operationsand to reduce production losses to a minimum, numerous screen changing methods and machines were'developed, the most efficientY 4of which is shown in my prior Patent No. 2,299,-

'746, dated October 27, 1942. Equipment of the kind shown in that patent, however, is necessarily heavy, somewhat complicated and expen Nevertheless, the economies eiected by thev use thereof more than justified the initial investment for such equipment.

The bronze screens of the prior art had to be handled with the greatest care during their in- Any bends or kinks in the wire, caused by mishandling would ruin. the screen and makeit entirely unsuitable for use, since the bends or kinks would form blemishes in the paper, clearly visible in the finished product.v

Moreoven'any disturbance of the relation of the individual wires, dents orother defects 'which might be caused by dropping tools or other foreign bodies on the wire during a screen changing `with the greatest of. care during its installation upon a machine, all of which materially added to the costoi the Fourdrinier machine.

illustration, and described below.

1 claim. (c1. faz-44) The ilexibility, toughness, and resilience of the non-metallic screen referred-to above makes possible a greatly simplified methodof installing the screen and a corresponding simplioation of the Fourdrinier machine. 4

In accordance with the present invention the complicated screen handling mechanisms of the prior art are entirely eliminated, thereby materially reducing the cost of the machine and facilitating the installation of new screens, bothas to cost and time involved. Y

A primary object of the invention is to provide novel supporting means on the tending side of a Fourdrinier machine, facilitating the installation of the lower run of an endless, ilexible, non-metallic Fourdrinier screen. Y

Another object is to provide means for handling the upper run of such a screen,-to carry it across the machine and to smooth out the same.

Another object of the invention is toprovide improved screen guiding and tensioning means adapted to cooperate with the ilexiha nonmetallic screen. Y ,Y

Still another object is to provide improved means iorsupporting the breast and couch rolls directly from the Fourdrinier frame.k Another object of the invention is to provide a Fourdrinier machine, adapted to cooperate with the new screen, and having an increased number of suction boxes associated therewith, whereby the speed of lthe screen may be increasedV or greater amounts ofwater removed irornjthe Wet web, if-,the speed is the same as heretofore.

Other andfurther-objects andl advantages of the invention will be apparent from a Vconsideration of the embodiments of the inventionlshown in the accompanying drawings for purposes lof In `the accompanying drawings, 1.5

Figure l is a diagrammatic side elevationof one form of apparatus embodying the invention, with sections of the Fourdrinier machine 'broken away; r Y l Figure. 2is adiagrammatic plan View ci a, portion of the tending side oi a Fourdrinier machine, illustrating a preferred method of installing a new screen;

Figure 3 is a View `similar to Figure l, showing a modied form of apparatus in which the breast and couch rolls are journalled in iixed bearings Figure 5 is a similar View of the couch end of the same machine;

Figure 6 is a transverse view, taken substantially on line 6 6 of Figure 4, showing a mechanism for carrying the screen transversely across the table;

Figure 7 is a similar view showing the parts at a later stage in the operation of installingv a screen, and Y Figure 8 is a diagrammatic side elevation showing a further modication.

As noted above, the present invention eliminatesthe expensive and somewhat complicated undercarriages and wire handling devices employed in constructions similar to my prior patent identied above and also eliminates the complicated mechanisms employed in known constructions, in which the Fourdrinier table and associated parts are moved transversely into the tending aisle for a Wire changing operation. Instead, simple removable or shiftable supports for the tending side of the frame are employed to carry out a novel screen changing procedure.

In Figure l a Fourdrinier machine ofthe fixed pitch, non-shaking type is illustrated, comprising a main frame having a longitudinal side member I0 on the tending side, supporting tabl'e rolls II and I2 and suction boxes I3 in the known manner. The breast roll I4 may be journalled in bearings I5 carried by arms I6, pivoted to av cross shaft I1 carried by the main frame members I0, after the manner illustrated in Figure 8 of my above mentioned patent, for swinging movement from the dotted position for paper making, to the lowered-full line lposition for aV screen changing operation.

The couch roll 20 may be supported independently of the table by stands, the forward one 2| of which includes a removable blocking section 22, and the rear one of which (not shown) is adapted to support the roll in cantilever fashion during a wire changing operation, when the blocking piece 22 is removed, as is well understood in the art and as is explained in my above mentioned patent. In this type of construction, the suction for the suction couch roll is usually connected through the stand and blocking piece on the tending side of the machine.

The frame I0 carries the usual downwardly projecting hangers 25, 26, on which the return guide rolls 21, 28 for the Fourdrinier screen are journalled. A tension or take-up roll 29 may be journalled in bearings at the ends'of arms 39,

pivotally mounted in floor-supported brackets 3 I, as is Well understood.

The driving side frame member (not shown) may be supported in the usual manner by xed stands, not shown. Novel supporting means for the tending side frame member I9 are provided, consisting of stands 35, 36, having removable blocking piecesY 31 and 38 associated therewith. positioned adjacent the breast and couch ends of the frame respectively. vertically adjustable jacks 39, 40, having screws 4I, 42 may be positioned between the stands 35, 36, cooperating with depending blocks 43, 43', carried by the frame III. The jacks are adapted to be operated by shafts 44, 45, extending rearwardly toward the driving side and actuated by suitable mechanism, not shown, rotation being imparted from the shaft to the nuts embracing screws by suitable gearing in the jack housings.

Thus, the frame Il! on the tending side of the machine is normally supported by the jacks and 4 the stands 35, 36 with the removable blocking pieces 31, 38 in place.

The operative paper making position of the Fourdrinier screen is indicated by the broken line 49, with the ends of the screen loop trained about the breast roll I4 and the couch roll 20, the upper run disposed above the table rolls and suction boxes and the vlower run below the frame or table, in engagement with the guide rolls 21, 28 and tension roll 29. When a new Wire is to be installed, the breast roll I4 is swung downwardly to the full line position below the table, and the tension roll 29 islowered.

The pliable, flexible non-metallic Fourdriner screen 59 may be folded, pleated, or rolled into a transversely compact bundle 5I and tied by tapes or the like 52 at appropriate intervals, to maintain the same in transversely compacted, longitudinally elongated loop form, as indicated in Figure 2. Such a screen may be installed by the following procedure:

First, the jacks 39, 49 may be lowered,leaving the frame supported exclusively at its ends on the tending side by the stands 35, 36, and the central section 52' of the lower run of the screen passed inwardly beneath the frame behind the jacks 39 and 40, above the roll 29 and below rolls 21 and 28.

Second, the jacks may be raised to support the frame on the tending side.

Third, the removable blocking pieces 31 and 38 may be removed and the adjacent portions 53 of the screen bundle passed through the openings so provided, beneath the ends of the frame.

Fourth, the blocking pieces may be replaced, so that the frame is supported jointly by the jacks and the fixed stands.

Fifth, with the couch roll supported in cantilever fashion, the removable blocking piece 22 may be removed and the end sections 54 of the bundled screen loop and the upper run 55 placed 'around the ends of the table, the breast and couch rolls and upon the upper surfaces of the table rolls and suction boxes.

Sixth, the screen may now be unrolled or unpleated and drawn across the machine and smoothed out from the tending side to the driving side.

Seventh, the removable blocking piece 22 may be replaced, the breast roll I4 swung upwardly to the operative position and the tension roll 29 raised to take up any remaining slack and to apply the desired tension to the screen.

This method of installing a screen is entirely `feasible with a flexible, non-metallic screen, since the bundling, handling and twisting of the material has no deleterious effect thereon and will not leave bends, kinks, or other imperfections in the screen.

In the form of the invention yshown in Figure 3, the Ibreast roll I4a and the couch roll 20a are supported directly by the Fourdrinier frame, and

this is facilitated by using an extra long screen and a novel take-up or tension device hereinafter explained, in connection with Figure 8. The side frame member Illa on the tending side and its mate onthe driven side may carry bearings I5a for the journal of the breast roll. Similarly, the suction couch 20a may be journalled in bearings 60, xedly attached to extensions 6I of the side frames Illa. The suction connection for the couch may be provided by a conduit i62 at the drive side, leaving the couch unobstructed at Vthe tending side.

Jacks 39a and 43a., and? stands 35a and 36al support" the frame member Illa as previously described. A tension roller 29a, however, maybe supported, when in the inoperative position by 'a hanger frame 65 carried by the table. Belowr the hanger and the roll 29a is a, pit 66, into which thefrcll 29a may movedownwardly Vto take up slack and to apply` tension, as more V'fully explained in connection with Figure'8.

lIn the operative, paper making position Ila of the screen, it is trainedloverfioor supported guide rolls 61, v6i? into the pit E6. The-method of changing a screen in connection' with" the apparatus' of yFigure 3 is substantially identical to that previously explained, with the exception that the tension roll 29a is maintained in the uppermost position, carried by the hanger 65 during the entire screen changing operation anda screen having a substantial excess length is employed, to facilitate manipulationk of the ends of the loop around the frame supported breast and couch rolls, and over the top of the frame, after the lower run has been passed beneath the table as previously described. The excess -or slack is taken up by the runs downwardly into andupwardly out of the pit 66, after the tension roll 29a has been loweredthereinto.

Y In Figure 4, avariable pitch Fourdrinier of the shaker type is illustrated, in `which the main frame members lill? are pivotally supported for tilting` movement 'at the breast end upon a bearing bar l0, seated at the upper end of pedestalsl 1I, the pedestal 'on the tending side being mounted for rearward swinging movement about a. pin 12, as explained in my above identified patent. The breast' roll, lib is adapted to be supported for downward swinging movement to anf'inoperative position by bearings I 5b, carried by arms IGb. When in the upper? operative position, the breast roll is journalled for'rotation in a, ywell--kncwn type of shaking mechanism '13,v including springs 'M and 15.

Shake rails 16, l1, connected to the main frame by springs T8 carry the usual table rolls |2b and .suction boxes l3b may be supported for transverse reciproication :adjacent the couch end of the tab-le in the usual manner.

The frame is supportedA on the drive side by xed,` stands EB, having slots 8| adjacent their upper ends, through which heavy bolts 32 carried'by the table project, so as to support the :s Atable at the rear side in adjusted, position.

Two pairs of jacks are provided, one pair for thev tending side land the other for the drive side. and all may be interconnected to raise and lower the frame to change the pitch thereof, by swingi.

ing the frame in a vertical plane .about the axis of the bearing bar 10. The jacks 39h and 4Gb on and, in addition, may be lowered to facilitate a screen changing operation in the manner previou-sly described. To thisvend, xed stands 3-5b ing brackets 85 having bifurcated upper ends in which pulleys 86 are journalled about horizontal the tending side perform this normal function stub shafts 81. The top of each vpulley is `disposed above the table rolls and suction boxes and the lower portion thereof below the lower edges of the side frame members. A rope, belt, or other strand or band 89 is trained about each pair of pulleys B6 with its upper run extending entirely across the machine, in position to support the upper run 55 of the screen' bundle 5l.

Any appropriate means may be provided to rotate the several pairs of pulleys in unison, or theymay ybe operated `by hand. Thus, when the edge 55 ofthe upper run of the screen on the tending side of the machine is held, andthe upper run of each bandmoves toward the drive side, as indicated by the arrows, Figures 6 and 7, the bundle will be unrolled, unfolded, or otherwise vopened up and carried entirely across themachine until its other edge reaches the tending side. Simultaneously, the screenwill be smoothed by the engagement of the supporting bandtherewith. The lower run of the screen, hanging below the table, will similarly be 4opened upand carried across the machine.

After the screen has been spread in thisv fashion, the ropes or bands 89, and, if desired, the pulleys '85 and their supporting moved.

After the breast roll lib, the pivot support?! and the tension roll 29h have been restored to their normal positions, the apparatus is ready for paper making operations.I I

In the form of the invention shown in Figure 8, the Fourdrinier may be of the fixed or variable pitch type, with shaking or non-shaking breast and table rolls, and the breast and couch rolls may be supported from the main frame or independently, as occasion may dictate. In the diagrammatic illustration of Figure 8, the main frame IGI) `carries shake railsV ll, supporting table rolls |02, in accordance with conventional practice, except that the numberof table rolls may be substantially reduced over that commonly used for a Fourdrinier .of given length.

Suction boxes |03 may be supported for oscillation across the machine, in the usual manner from rails |04, or stationary suction boxes may well be employed with the new pliable, flexible,

`brackets 85, may be retough, non-metallic screen referred to above.'

The number of suction boxes may be materially increased, as indicated in Figure 8, since the new screen is much more vresistant to friction than conventional bronze wire screens andV can readily withstand, without undue. wear, the frictional contact with an increased number of boxes. The increased number of suction boxes, of course, removes a greater percentage of water from the wet paper web and, therefore, reduces the Water removing task performed by the press section and the drying rolls in the line, The drying sections of conventional paper machines are extremely long, occupy a large amount ci' space, are costly to install and consume tremendous amounts of power in the form of heat, simply to get rid of the Water in the paper web. Anything that can be done at the Webforming end of the machine to remove larger amounts of water is of great utility, in reducing the size and expense of the drying section of the machine.

The number of suction boxes heretofore used was limited by the friction factor. That is to say, if the number of boxes were increased, the friction with the Wire was increased and the life of the wire was correspondingly reduced. Hence, it was economical to use fewer suction boxes and basement.

more drying rolls, in order not to shorten unduly the life of the wire screen.

The breast roll and the couch roll |06 may be supported by the frame |00 or independently, as desired. The return guide rolls |01, |08, |09 and I I0 may conveniently be journalled in stands carried by the mill floor. The last mentioned two rolls are positioned adjacent to the open upper end of a pit III extending downwardly through the mill iloor I I2, to the floor I I3 of the When in operative position, .the screen IIB is trained downwardly into the pit, around a tension guide roll III, having its ends iournalled in vertically adjustable brackets mounted upon screws or the like associated with the side walls of the pit, for vertical adjustment of the roll.

, The roll II'I, during a screen. changing opera- .tion is carried by brackets or a cage IIS, secured to theundersurface of the frame |00.

Another guide roll |20, adjacent the breast lend of the machine may be hungin journals carried by the frame |00. Y

On `the tending side of the machine, the frame issupported adjacent its ends by stands I25` and I 2.6, having removable blocking pieces |21, |28 associated therewith, and by vertically adjustable jacks |30, I3I, as previouslydescribed. It will be understood that, if the machine is of the xed pitch type, the jacks will be positioned on the tending side only but that if it is of the variable pitch type a similar pair will be disposed beneath the frame on the drive side.

A Fourdrinier screen of excessive length may be used with a machine of the type shown in Figure 8, thereby providing the necessary slack to facilitate a screen changing operationv and also greatly lengthening the useful life of the screen, due to the reduced frictional Contact of any point on the screen with the friction producing element.

v In the operating of changing a screen, the procedure outlined above is followed, except that the tension roll I I'I is raised into the bracket I I 8 and held in that position beneath the frame.

Thejacks |30 and I3I will be lowered and the lower run of the bundled screen placed in position therebehind, with any excess draped downwardly into the pit III over the rollers |09 and IIO. The jacks are then raised and the blocking pieces IZ'I and |28 removed, whereupon the remainder of the bottom run of the screen may be placed under the table and the ends of the loop draped around the breast and couch rolls, with the upper run positioned above the frame on ropes or the like, similar to those shown in Figures 4, 5, 6, and 7, but omitted from Figure 8 for the sake of clarity. The screen may then be unbundled and smoothed across the machine as previously described. The tension `roll II'I may be lowered into its vertically adjustable brackets in the pit III, and adjusted to the proper position, to apply the desired tension, whereupon the machine is ready for operation.

'Ihe invention is not limited to the details of construction and arrangement of parts, or to the exact method described above, but includes all constructions and methods comingV within the scope of the appended claim and their equivalents.

I claim:

In combination with a. Fourdrnier machine, supporting means for the tending side of the Fourdrinier frame facilitating installation below the-frame of the lower run of an endless, highly Flexible, non-metallic forming screen, bundled into a transversely compact, longitudinally elongated loop, and means for opening up the bundied loop and carrying the screen across the machine and smoothing the upper run thereof across its length, said second mentioned means comprising la plurality of pairs of pulleys, means for supporting one pulley of each pair from the frame at the tending side and the other at the drive side with the pairs in transverse alignment, and a band trained around eachpair of pulleys with its upper run above the frame and its lower run therebelow, the upper run of each band being adapted to support the upper run of the bundled screen adjacent the tending side, whereby when the tending side edge of the screen is held stationary, the remainder may. be carried toward the drive side and smoothed out, by moving the upper runs of the bands toward the drive side.

HARRY H. HART.

REFERENCES CITED The following references are of record in the file of this patent:

` UNITED STATES PATENTS Hart Oct. 27, 1942 

